Compass ellipsograph



May 29, 1923.

J. A. CALDWELL COMPASS ELLIPSOGRAPH Filed Oct- 20. 1921 ,ZruuenZa y, JLMZZMZZ Patented May 29, 1923.

COMPASS nnnrrsoennrn.

Application filed October 0. 1921; Serial in. 509,172.

To all whom it may concern:

Be it known that I, JOHN A. CALDWELL,

a citizen of the Dominion ofCanad-a, residing at Vancouver, 1n the Province of British Columbia, Canada, have invented certain new and useful Improvements in Compass Ellipsographs, of which the fol lowing is a specification.

This invention relates to an ellip'sograph which is an improvement on that on which Patent No. 1,235,108 was granted to me on the 31st July, 1917.

The invention is fully set forth inthe following specification,-; reference being made to the drawings by which it is ac-' companied', in which 7 Figure 1 is an elevation view of the instrument showing the device as applied to trace an ellipse.

Fig. .2 is a top view of the attachment of the axial stem or front leg to the supporting leg. j

Fig. 3 is a section through the attachment of the axial stem to the upright leg.

Fig. 4 is part elevation showing a full ellipse-traced without the axialleg or "the back leg being moved.

Fig. 5 is a face view of the foot.

Fig. 6 is a top view of a sliding sleeve with two arms at right angles firmly atsupporting tached thereto, and also the top of the pencil carrier with knurled nut.- 1

Fig. 7 is a section of the center point of the axial leg.

Similar numerals refer to simllar parts.

In these drawings 2 represents an up-::

right 'or supporting leg of unifornr cross section, which leg is pointed at its lower end l-and has removably attached a foot 3 which has two offsets at right angles to the face which engage point 4: through which it passes and enables leg 2 to be held firmly in an upright position.

The upper end of supporting leg 2 passes through a yoke-sleeve 5.and through it is endwise movable, this yoke-sleeve 5 is provided with a clamp 8- which fits the contour of leg 2. The clamp 8 is tightened against the leg by a knurled headed clamp screw 9 which is threaded through the rear wall of yoke-sleeve .5. To this yokesleeve 5 is pivotally connected by things joint 6 a front leg 10 of uniform cross section with leg 2, said leg 10 is provided on'the bottom end with a removable point 11. This point small ellipses only; i

' major axis with foot 4 major axis.

is fiatte nedjon-face and'rear having 'aV* 1 shaped slot in the'center forming a double point between which a smallpin 18 may be inserted and so. retain point-11inthej center. 1 1

On leglO a, sleeve 12' is freelv-Inovable f having firmly formedthereontwofjgraduated *radiusbars 13 and 14 located on the, g

upper and under endsof'the sleeve 12'and on opposite sidesand of,different-lengths.

011 bar leis sh'own'aremovableslidingpen w cil'holder 15"threaded on the upper end and having a slot formed across the center to fiton the graduated barsor arms' and provided with a knurled nut '16 and'wash'er on the threaded end. ing a socket to hold a inserted therein. i 3

At Figure-4: isshowna part elevation in edge of the arm, it-can be seen by "Figure of the major axis to the other. This form- Theunder end havl pencil 1T firmly when T i which only the .one short. radius arn -is shownon the bottom-end ofth'e-sleeveand the pencil holder mounted on the reverse of the sleeve with, one short arrnis for To uselthe instrument forsmall ellipses.- thema or and I minor'axes belng. known,

the: pencil is set to half them'inor'axisby' s sliding carrier 15 along the graduated radiusarm 1e and secure :itwith the knurled 1 nut 16 a small pin 18- is inserted in-the intersection of the major and minor axes and point 11 0f :legilO placed against the the pivot 6 and clamp8 may be clamped in yoke-sleeve 5 to supportleg 10 in that position, point. 4 being on the extended at right angles to the The tracing pencil 17 .pin 18 the instrument lbeing upright the] yoke-sleeve 5 beingslightly 'slacke ned and the legylO: inclined until the .pencil point 17 is at the adjacent end of the major axis Q j' mounted on arm; 14 .1

maybe started at one end of the minor axis' to the half of which it has been set the sleeve 5 12 will inove up leg 10 as'the pencil traces the curve of the ellipse until the end of the major axis is reached and will. then move gradually; around and down the leg while tracing the other quarter. The leg 2may then Y 1 be transferred to a corresponding position on of the ellipse totrace theother half.

the'major axis produced on the opposite side j i Y which bring them, more central Arm 14 is to be used for small ellipses as the pencil holder may be placed against sleeve 12 and scribe very small ellipses without the end of arm 14 coming in contact with the surface to be traced on, therefor the long arm 13 is required for larger ellipses.

- nected t said sleeve, a second sleeve pivotally and slidably mounted on said second leg, graduated arms extendin radially from I and] in opposite directions on said second sleeve, a marking device adapted to be slidably mounted on either ofsaid arms, and means for clamping said device toeither 2. A compass ellipsograph, comprising in combination a compass leg, pointed at one ,end a foot removably clamped on said pointed end for supporting the said leg in an,

upright position, offsets on the outer face of the foot bet-ween which the leg point pro ects, a yoke sleeve through which said leg 15 movable endwise with means for clam in it in any position of endwise adjustment,a second leg having a removable double pointed end, the said leg being pivotally connected to said yoke sleeve, means on. the pivot and yoke .sleeve for clamping said legs at any angular adjustment and with respect to each other, a two armed radius sleeve freely movable on pivot leg, a tracing point holder adjustable on either of radius arm and means t secure it thereon in any desired position,

A. compass ellipsograph, comprisingin combination a tubular leg pointed on one end, means removably attached to the pointed end for supporting said leg perpendicularly, a yoke sleeve through which this leg is movable, means for securing it at any desired position of endwise adjustment, a second tubular leg pivotally connected to said yoke sleeve, means for securing said second leg in any position of angular adjustment, on the first leg a removable point, flattened on front and rear liaving a V shaped notch to receive a central steadying pin, on said second leg, a sleeve having a long and short graduated radius arm, a tracing point holder, means for holding said holder in adjusted position on either arm, and a tracing point socketed in the under end of said holder.

In a compass ellipsographcomprising in combination a tubular leg pointed on one end a foot removably attached to the pointed end, said foot having two central offsetsprojecting beyond the plane of thefoot between which t-he pointed end of said leg projects in line withthe two ends of the foot to support said leg in anupright position, a yoke sleeve in which said leg is endwise movable, a clamp provided with a knurled headed clamping screw, threaded through the rear of the yoke sleeve to bind said legin endwise adjustment, a tubular front leg' pivotally connected to the said yokesleeve a knurled nut on the end of the pivot pin together with the back clamping screw in said yokesleeve t secure the pivoted leg in the angular adjustment required, a removable point socketed in the free end of the said leg, a radius sleeve freely movable on this leg, said sleeve having a graduated short arm at one endiat right angles to the axis and a longer graduated radius arm opposite endand oppositeside, a pencil or'tracing point holder provided with a slot adjustable on either arm a knurled nut threaded on the upper end of said holder above the; arm slot to secure it in the position required, the said holder being provided with a socket on the under end to holda tracing pointrfirmly in a central position.

JOHN A. .CALDW ELL. 

